Volumetric and Material Balance Methods of Reserve Estimation: A Comparative Study using Niger Delta Reservoirs

Two producing reservoirs (H10 and E40) in Eni field Offshore Niger Delta were studied with intent to enhance their rate of recovery while mitigating water production. The material Balance software MBAL was used to estimate the Stock tank oil reserves and then compared to reserve estimates determined by both deterministic and stochastic techniques for improved validation. The MBAL model was also used to identify positions of fluid contacts and determine predominant drive mechanisms. These serve as guide in making informed decisions towards if and how best to economically produce remaining unproduced oil in place. Input parameters were average values derived from core and well logs analyses. History matching of historical data enabled forecasts of possible future production life and volume at multiple scenarios. Final outcomes show that after sixteen and forty five years of continuous production from the reservoirs studied (H10 and E40, respectively), remaining unproduced oil in place are still significant and can be economically produced by infill wells, which will in return increase the average production by nothing less than 33% of remaining oil in place, a substantial value bearing in mind the growing demand for oil, gas and other energy sources to lessen the apparently unquenchable world energy needs.

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A comparative study of geometric and geostatistical methods for qualitative reserve estimation of limestone deposit

Geoscience Frontiers ◽

10.1016/j.gsf.2020.02.019 ◽

2021 ◽

Vol 12 (1) ◽

pp. 243-253

Author(s):

Thomas Busuyi Afeni ◽

Victor Oluwatosin Akeju ◽

Adeyemi Emman Aladejare

Keyword(s):

Comparative Study ◽

Reserve Estimation ◽

Geostatistical Methods

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Effect of Kerogen Thermal Maturity on Methane Adsorption Capacity: A Molecular Modeling Approach

Molecules ◽

10.3390/molecules25163764 ◽

2020 ◽

Vol 25 (16) ◽

pp. 3764 ◽

Cited By ~ 1

Author(s):

Saad Alafnan ◽

Theis Solling ◽

Mohamed Mahmoud

Keyword(s):

Molecular Modeling ◽

Adsorption Capacity ◽

Gas Adsorption ◽

Material Balance ◽

Methane Adsorption ◽

Source Rocks ◽

Thermal Maturity ◽

Reserve Estimation ◽

Adsorbed Gas ◽

Key Factor

The presence of kerogen in source rocks gives rise to a plethora of potential gas storage mechanisms. Proper estimation of the gas reserve requires knowledge of the quantities of free and adsorbed gas in rock pores and kerogen. Traditional methods of reserve estimation such as the volumetric and material balance approaches are insufficient because they do not consider both the free and adsorbed gas compartments present in kerogens. Modified versions of these equations are based on adding terms to account for hydrocarbons stored in kerogen. None of the existing models considered the effect of kerogen maturing on methane gas adsorption. In this work, a molecular modeling was employed to explore how thermal maturity impacts gas adsorption in kerogen. Four different macromolecules of kerogen were included to mimic kerogens of different maturity levels; these were folded to more closely resemble the nanoporous kerogen structures of source rocks. These structures form the basis of the modeling necessary to assess the adsorption capacity as a function of the structure. The number of double bonds plus the number and type of heteroatoms (O, S, and N) were found to influence the final configuration of the kerogen structures, and hence their capacity to host methane molecules. The degree of aromaticity increased with the maturity level within the same kerogen type. The fraction of aromaticity gives rise to the polarity. We present an empirical mathematical relationship that makes possible the estimation of the adsorption capacity of kerogen based on the degree of polarity. Variations in kerogen adsorption capacity have significant implications on the reservoir scale. The general trend obtained from the molecular modeling was found to be consistent with experimental measurements done on actual kerogen samples. Shale samples with different kerogen content and with different maturity showed that shales with immature kerogen have small methane adsorption capacity compared to shales with mature kerogen. In this study, it is shown for the first time that the key factor to control natural gas adsorption is the kerogen maturity not the kerogen content.

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A comparative study of aggression amongst Nigerian University students in Niger Delta region

Psychology Health & Medicine ◽

10.1080/13548506.2010.507775 ◽

2011 ◽

Vol 16 (1) ◽

pp. 86-93 ◽

Cited By ~ 5

Author(s):

Festus Abasiubong ◽

Tajudeen Abiola ◽

Owoidoho Udofia

Keyword(s):

University Students ◽

Comparative Study ◽

Niger Delta ◽

Delta Region ◽

Niger Delta Region ◽

Nigerian University

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Using Different Methods to Predict Oil in Place in Mishrif Formation / Amara Oil Field

Iraqi Journal of Chemical and Petroleum Engineering ◽

10.31699/ijcpe.2020.1.5 ◽

2020 ◽

Vol 21 (1) ◽

pp. 33-38

Author(s):

Mohammad Najeeb ◽

Fadhil Sarhan Kadhim ◽

Ghazwan Noori Saed

Keyword(s):

Reservoir Simulation ◽

Material Balance ◽

Volumetric Method ◽

Oil Field ◽

Percentage Error ◽

Reserve Estimation ◽

Volume Calculation ◽

Monte Carlo Simulation Technique ◽

Hydrocarbon Content ◽

Decline Curve

The reserve estimation process is continuous during the life of the field due to risk and inaccuracy that are considered an endemic problem thereby must be studied. Furthermore, the truth and properly defined hydrocarbon content can be identified just only at the field depletion. As a result, reserve estimation challenge is a function of time and available data. Reserve estimation can be divided into five types: analogy, volumetric, decline curve analysis, material balance and reservoir simulation, each of them differs from another to the kind of data required. The choice of the suitable and appropriate method relies on reservoir maturity, heterogeneity in the reservoir and data acquisition required. In this research, three types of reserve estimation used for the Mishrif formation / Amara oil field volumetric approach in mathematic formula (deterministic side) and Monte Carlo Simulation technique (probabilistic side), material balance equation identified by MBAL software and reservoir simulation adopted by Petrel software geological model. The results from these three methods were applied by the volumetric method in the deterministic side equal to (2.25 MMMSTB) and probabilistic side equal to (1.24, 2.22, 3.55) MMMSTB P90, P50, P10 respectively. OOIP was determined by MBAL software equal to (2.82 MMMSTB). Finally, the volume calculation of OOIP by using the petrel static model was (1.92 MMMSTB). The percentage error between material balance and the volumetric equation was equal to 20% while the percentage error between the volumetric method and petrel software was 17%.

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